It provides power for the Boeing 747-8 and its predecessor, the PW901A-powered Boeing 747-400. During on-ground operation, it provides bleed air for cabin conditioning from a low spool-driven load compressor, and electrical power from two gearbox-mounted 90kVA generators.

2016年10月24日 · When the N2 rotor speed is 8%, the APU controller energizes the ignition exciter and sends a signal to the fuel metering unit to supply fuel to the combustion chamber. The ignition exciter causes the two igniter plugs to make sparks. The APU engine has combustion and starts to increase in speed.

2009年12月27日 · Auxiliary Power System (APS): The APS comprises the auxiliary power unit (APU), and the inlet, exhaust, control, and mounting hardware. The first all electric APU will be 50 percent quieter and have 10 percent lower emissions compared to the Boeing 767 APU. B747-8 Pratt & Whitney APU PW901A, same as installed in 747-400 series.

The 747 Auxillary Power Unit, or APU, is a gas turbine engine that is housed in the tail section of the aircraft. The APU can supply electrical and pnuematic...

The implementation and installation of Boeing's 747 auxiliary power unit (APU) was the result of efforts tailored to the 747 airplane's needs. Greater power requirement of the plane and its size made unique demands in formulating an APU design specification.

2015年7月25日 · The Boeing 747-400 APU is a variant of a Pratt & Whitney turbofan engine used on Cessna Citation and Mitsubishi Diamond business jets. This is a very powerful engine. It takes a lot of horsepower to run the systems on the 747 when the main engines are shut down.

2021年9月24日 · This course does an excellent job of describing the components, normal/abnormal operations, controls, indications of the B747 APU and includes the following information: The APU systems to include the start and shutdown procedures for normal and abnormal conditions.

2022年5月4日 · 747使用的APU型号是PW901，有两个转轴，分别为N1轴和N2轴，N1轴是低压轴，连接动力涡轮和负载压气机，负载齿轮箱等，在正常运行时保持100%的转速。 N2轴是高压轴，连接高压涡轮和高压压力机。 N1轴和N2轴分别使用一个转速传感器来感受转速。 每个传感器都有两个线圈，一个线圈给APUC转速信号，用来控制转速和显示，另外一个给APUC的转速信号用来超速关断。 当N1转速超过110.8%，或N2转速超过103.2%时，APUC会控制APUC关车。 …

2009年12月1日 · The EICAS message APU indicates that the APU is unusable; no further attempt should be made to use the APU until maintenance clears the fault C. If the APU continues to operate after the APU Selector is OFF, the APU may be shut down manually by …

2016年10月26日 · "If the door fails to open to a position greater than 13 degress, the electrical circuitry of the APU prevents the APU from starting". These maintenance training notes do have a common source (Boeing), but each airline adds their own text modifications to suit their aircraft.